This invention relates in general to aircraft ground power connector systems for providing electrical power to aircraft when they are on the ground with engines and auxiliary power units turned off. In particular, the invention concerns connectors attached to power cables and having replaceable elements.
Most aircraft are equipped with power connectors, such as a male plug receptacle recessed into a cavity of the aircraft for protection. A mating female connector having a power cable attached thereto is plugged into the male connector when power is needed on board the aircraft. However, the female connector is subjected to considerable abuse from abrasion due to falls against the concrete or asphalt surfaces on which the aircraft is located as well as degradation due to exposure to weather and petroleum products.
Very early ground power cable and connector systems included a number of single conductors banded together at intervals and connected to the contacts in the connector. Because the bands were metallic, abrasion against concrete or asphalt surfaces would make the bands razor sharp and therefore a significant cut hazard.
These early connectors lacked any switching capability. Further, the contact members of such connectors would lose their gripping force with use, and the weight of the connector combined with the weight of the cable would cause the connector to drop out of the aircraft receptacle and fall to the ground.
To overcome these early cable and connector shortcomings, switches have been provided within the connector body so that the power could be turned on and off at the aircraft without walking back and forth to some remote switching location. See, for example, my prior U.S. Pat. No. 4,758,175, which is expressly incorporated herein by reference. Also, control conductors were included in the power cable to provide remote power switching capability in a single sheath, thereby providing protection for the small control conductors, which also eliminated the need for banding the conductors and the problems associated with the metal bands. The small control conductors are connected to switches in the connector body. The power conductors are attached to contacts in the connector head. However, to overcome the loss of the contact gripping power which resulted in the connector falling out of the aircraft receptacle, the newer connector designs add a replaceable nose section complete with additional contacts integrally molded therein and which plug into the contacts which are molded into the connector body. See, for example, my prior U.S. Pat. No. 5,256,081, which is expressly incorporated by reference herein. However, the added nose section increases the overall connector length and weight with the result of diminishing the gripping forces on the aircraft receptacle contacts, thereby making the connector more susceptible to dropping out of the aircraft receptacle. Further, the replaceable nose section adds an additional set of contacts in the connector, which doubles the electrical power loss due to the electrical resistance of engaged contacts which results in increased heating of the connector.